Thermal inactivation of avian viral and bacterial pathogens in an effluent treatment system within a biosafety level 2 and 3 enhanced facility.

Authors: Chmielewski, Revis; Day, James; Spatz, Stephen; Yu, Qingzhong; Gast, Richard; Zsak, Laszlo; Swayne, David

Submitted to: Applied Biosafety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2011
Publication Date: 12/20/2011
Citation: Chmielewski, R.A., Day, J.M., Spatz, S.J., Yu, Q., Gast, R.K., Zsak, L., Swayne, D.E. 2011. Thermal inactivation of avian viral and bacterial pathogens in an effluent treatment system within a biosafety level 2 and 3 enhanced facility. Applied Biosafety. 16:206-217.

Interpretive Summary: Wastewater from high and low biocontainment laboratories must have all pathogens killed in solid, liquid and aerogenous biological waste, before disposal. Wastewater (effluent) generated from these facilities included water from laboratory sink and floor drains, animal room floor drains, showers, and autoclaves. To ensure wastewater discharge is not contaminated with live microbial pathogens the effluent must be inactivated prior to release to the public sewer system. The validation process in phosphate buffer system with avian influenza, Newcastle disease virus, reovirus, rotavirus and astrovirus showed that 6.4-8.8 log10 virus/ml were inactivated at 82.2 degrees Celsius within 3 min of exposure. Enveloped and non-enveloped viruses including avian influenza (AI), avian paramyxovirus Type 1 (AMPV-1), reovirus, rotavirus, turkey astrovirus (TAstV), avian metapneumovirus (aMPV), Marek’s disease virus (MDV) and avian parvovirus (ChPV) were exposed to standard effluent decontamination (EDS) inactivation cycle of 82.2 degrees Celsius for 6 hours. The EDS heat treatment totally inactivated enveloped and non-enveloped virus with inactivation levels ranging from 5.1 to 11.1 log10 virus/ml.

Technical Abstract: Avian influenza (AI) virus, avian paramyxovirus Type 1 (APMV-1 or Newcastle disease virus [NDV]), reovirus, rotavirus, turkey astrovirus (TAstV), avian metapneumovirus (aMPV), Marek’s disease virus (MDV-1), avian parvovirus (ChPV) and Salmonella enterica serovar Enteritidis are significant biosafety level 2 (BSL-2) or biosafety level 3 enhanced (BSL-3E) pathogens of poultry that are studied in veterinary medical research laboratories worldwide. The purpose of this study was to determine the effectiveness of a moderate temperature, effluent decontamination system (EDS) to inactivate avian pathogens. First, the thermal inactivation processes for AI virus, APMV-1, reovirus and rotaviruses were determined in phosphate-buffered saline (PBS) using in-vitro assays from which thermal death rates (Dt) and changes in heat resistance (zD) of the AI virus and APMV-1 were determined at various time/temperature parameters. The PBS validation process demonstrated that 6log10 reduction was achieved following heating at 82.2 degrees Celsius within 30 sec for AI virus and APMV-1, 1.8 min for astrovirus while reo- and rotaviruses were destroyed within 3 min. Second, to determine whether pathogens were adequately inactivated in moderate temperature EDS system, vials containing avian viruses (5.1-11.1 log10 tissue culture infectious dose (TCID) 50/ml or infectious particle/ml) and bacteria (9.1 log10 cfu/ml) were placed in the effluent tank and exposed to a standard cycle of 82.2 degrees Celsius for 6 hours. The EDS process totally inactivated enveloped and non-enveloped viruses with complete inactivation of greater than 5.1 to 11.1 log10 TCID/ml of specific pathogens. The data from the inactivation models and the EDS validation test showed that the 6log10 reduction required for sanitary assurance level of effluent was achieved with a significant margin of safety.